You could line it, sure! I would use something stretchy, of course. I'm not much of a sewer (I never realized until now that this could have two meanings!) Ahem. I don't sew much, but you could stitch in a liner.

Yah - that's probably why I don't make hats ... can't wear them :( Well I can, but then my hair would look like I stuck my finger in an a/c outlet!! It doesn't so much make my hair fall out as it destroys my curl pattern... Arrgggh! Maybe Silver can make suggestions; I think she's familiar with a sewing machine...